Regulating pump



L dill 2f April 2.1, 1942- s. MEgswlNKEL 2,280,248

REGULATING PUMP lNVEfNTORf SAMUEL MEIWINKEL ATTRNEJ/s S. MEISWINKELREGULATING PUMP Filed Jan. 17, 19:59

Apil 21, V1942.

2 sheets-S115@ 24 INVENT' OR. AML/EL-J MEJwINKL-:L

M AML ATTO'RNEG `Patented Apr.721, 1942 n lan(iULAnING PUMP SamuelMeiswinlrel, Gaggenau, Germany, assignor to Daimler-BenzAktiengesellschaft, Stuttgart-Unterturkheim, Germany .ApplicationJanuary 17, 1939, Serial No. 251,326

i In. Germany January 22, 1938 35 claims. l (c1. 12s- 140) Thisinvention relates to an apparatus for `limiting the maximum speed ofinjection internal combustion enginesv by regulating the fuel feed,

and has for itsobject to'effect in a'very simple manner andi withoutseparate mechanical or pneumatic auxiliary equipments, a reliable andaccurately operating control of the internal combustion engine for thepurpose of limiting its maximum speed of rotation.

For limiting the maximum speed of `injection internal 'combustionenginesby the regulation of the fuel feed, a constant factor and a variablefactor are, according to the invention, brought into alternatingrelationship in such amanner that when the constant factor is exceeded,the fuel feed to the cylinders is reduced by the variable factor, thevariable factor being a function of the speed ofrotationof the engine;The said variablefactor is determined by the quantity of fuelflowingback from the pump cylinder per unit of time andincreasing as thespeed of rotation increases. The quantity of lfuel flowing `back perunit of time acts directly or indirectly on the adjustment of a slidevalve controlling the feed passages, the returning fuel and the fuel fedfrom the tank beingjbr'ought together each from `one side of the slidevalve, so that when a certain speed is attained a dynamic pressure isproduced which constitutes the means for controlling thefuelfe'ed.`

For carrying out the objects of this invention, a `fuel pump withcontrolled commencement of feed and constant end of feed `is used sothat the injection adjustment is automatically coupled with thequantitybf fuel fed,xtha`t` is, retarded ignition takes place at lowload and a small quantity fed, and `advanced ignition at heavy loadwhich approximately corresponds `to the maximum speed. The arrangementis such that the `controlling element on the one hand is undertheinfluence of the constant factor and on the other `hand underthe`influence of the variable factor which on exceeding the constantfactor* adjusts the controlling element and throttles the fuel feed by`changingthe passage cross-sectional area. -For this `purposeacontrolling element `The controllingelement may consist of one orseveral rotary slide valves `to which the fuel from the tankws freelyiromoue side but from J the other side (by-pass-fuel) through anozzlewhich is arranged in such a manner that,when a predetermined feed isexceeded dynamic pressure lis produced on the inlet side of the `nozzleand adjusts the controlling element. The throttling device may beconstructed as a nozzle with adjustable throttling cross-section. 'I'hecontrolling element itself is, according to the invention, arranged as arotatable or axially shiftable piston-shaped slide valve in theinduction conduit, and has on its periphery'one or more controllingapertures or controlling edges which at the adjustment of the slidevalve alter by throttling the passage cross-section of the conduit, i.e. the quantity of fuel sucked by the pump. The controlling aperturesorfedgesof the slide valve are at the same time preferably constructedas peripheral tapered grooves or ports varying in depth, which controlthe inlet bores or channels leading to the pump.

The invention also` relates to-a device for adjusting the individualpump pistons for the purpose'of compensating inaccurate machining. A

' This independent adjustment is rendered possible, according to theinvention, in that the feed pistons,each provided inan upper portionwith a bevelled `edge, and which are not rotatable when running, areturned when adjusting the pump, for example on the test bench, and xedin the position which has been found to be correct, so that thenecessary quantity delivered by these pistons can be very accuratelycontrolled in each case. The adjustment is effected, for example, bymeans of a` toothed.r sector rigidly connected with the piston and whichallows of an adjustment through a 4very small angle. Thus, the bevellededge of each piston is adjusted relatively to the admission channels insuch a manner that the commencement of feed` of the individual pistonscan be accurately determined independently of each other. The pistonsare secured in the determined position, for example from the exterior,by means of a set screw which locks the toothed sector and consequentlythe piston rigidly connected therewith.

. This adjustingdevice possesses the advantages that unavoidableinaccuracies in machining can be compensated in a simple manner when thepump is Vbeing adjusted, andthat the adjustment can be carried out in ashort time from the outer side without any fitting work being necessary.

`The invention also relates to such a construction of the pump cylinderswhich enables them to be produced and machined in a particularly simpleand @heap mann-er'- According to the invention, the casing having thebores and passages is made of cast-iron, preferably cast pig iron, andthe cylinder bores and also the passages controlled by the piston arebored in separate rigidly inserted liners made of high grade material.The liners made for example of steel are cast, pressed or shrunk intothe casing as a solid body before the different holes and passages arebored. The advantages are thus obtained that the machining is extremelysimple and the position of the bores and control edges is alwaysaccurate.

Several embodiments of the invention are illustrated diagrammatically byWay of example in the accompanying drawings in which:

Fig. 1 is a section through the fuel feed pump taken on line 2--2 ofFig. 2 and viewed in the direction of the arrow;

Fig. 2 is a section on line I I of Fig. l;

Fig. 3 is a top plan view in section on line 3--3 of Fig. 2;

Fig. 4 is a sectional detail view showing an adjustable throttlingnozzle;

Fig. v5 is a section through a pump cylinder with adjusting device forthe feed piston;

Fig. 6 is a top plan View in section on line 4--4 of Fig. 5; and

Fig. 7 is a section through a pump cylinder with a liner.

The fuel pump Il) has an inlet passage Il and a return passage I2 whichare connected the one with the other by a channel I3. Pump pistons I5are arranged in'the cylinder bores or spaces I4 and moved by suitablecams of a cam shaft slide valve I9 in the form of a piston-shaped '1inhollow sleeve provided at one end with a nozzle or throttle opening 20moves in the inlet passage I I. The stroke of the slide valve I9 islimited on the right by an adjustable stop screw 2i and on u the left byan adjustable stop 22. The arbitrary 5 control of the internalcombustion engine is effected through the intermediary of theaccelerating lever (not shown) which turns the piston I5 or the edge 23thereof through the regulating or `adjusting device 24.

The fuel flows from a container, not illustrated, through a conduit 25and the openings 46, that is from the side remote from the nozzle 20, tothe slide Valve I9. The piston I5 controls by suitably shaped edges theadmission channel I'I and the overflow channel It in such a manner thatthe y fuel is forced through the conduits 26 into the cylinders of theinternal combustion engine, and

after having performed part of a predetermined stroke, a uniformquantity of fuel is fed through the piston bore 2'I and the recess 28into the overflow channel I8 and thence into the return passage I2. Theslide valve I9 has tapered grooves 29 and openings or bores 30 in itswalls, which,

together are arranged to form ports registeringv with the channel I'Iand act in such a manner that the effective cross-section of the inletpassage II leading to the cylinders I4 can be altered.

The operation of the regulator is the followings.

When the internal combustion engine and conr sequently the pump shaft I6are running at a low` speed, a quantity of fuel corresponding to thestroke space is sucked into the cylinders I4 as the piston I5 descendsand is injected into the cylinders of the internal combustion enginel ibustion engine.

through a suitable delivery passage at the correct time during theascent of the said piston. As soon as the recess 28 reaches the overflowchannel I8, the excess fuel ows back through the channels I2 and I3 intothe inlet passage II from which it is again sucked into the cylinders.At the same time the spring 3l presses the slide valve I9 towards theleft, so that the conical grooves 29 expose the largest passagecross-section to the cylinders I4. If the speed of the internalcombustion engine increases and attains a predetermined maximum, thequantity of fuel iiowing back in a unit of time is so high that at thethrottle point 20 counter pressure is produced which shifts the slidevalve I9 towards the right in overcoming the force of the spring 3| andthe pressure of the fuel within the passage II, and reduces theeffective cross-section of the passage I I to the pistons I5corresponding to the reduction in cr-oss-section of the tapered grooves29. Thus, the charge in the cylinder spaces I 4 during the descent ofthe piston Will be reduced and a correspondingly less quantity of fuelwill be injected into the cylinders of the internal com- The by-passquantity per piston stroke remains the same at all speeds. Owing to thedrop in pressure which then occurs in the by-pass conduit a slightoscillation of the regulating slide Valve I9 will take place until thisvalve has formed relatively the smallest possible feed cross-section ofthe entrance to the admission channels I'I necessary for the maximumnoload speed.

Fig. 4 shows a form of construction in which the throttle 23 can bevaried in cross-section by a needle 32.

According to the form of construction illustra-ted in Figures 5 and 6,the pump pistons I5 are pressed tightly against the cams 35 of the fuelpump shaft I6 by springs 33 which bear at one end against a springwasher 34 and at the other end against a spring Washer 35. The pistonsI5 have milled faces 31 on to which the slotted toothed sectors 38 canbe slipped from the side. These toothed sectors 38, which arenonrctatable on the pistons but longitudinally shiftable thereon, arefixed by suitable locking devices shown as set screws 39 from the outerside. By turning the toothed sectors 38 the bevelled edges 23 of thepistons I5 are adjusted relatively to the admission channels I'I, andconsequently the quantity delivered by the individual pistons can beregulated independently the one of the other. The pistons I5 also haverecesses or grooves 29 and bores 21, through which the excess fuel canflow off through the overflow channels I8 to the return passage I2. Thechannels I'I and I8 are closed at their outer ends by plugs 43 and 4I,respectively.

According to the example illustrated in Fig. 7, the cylinders d2 inwhich the pistons I5 move, are constructed as steel liners 43 which arecast, pressed or shrunk into the casing I0, for example a pig ironcasing. The casing may be made of light metal and produced for exampleby diecasting. The liners 43 are preferably inserted in the casing assolid bodies before the different holes and passages are bored(admission channel I1, overflow-channel I8' and so forth). Thus, themachining of the liner 43 is simplified considerably, the edges of thechannels I1 and I8 will be accurate and the resistant material sharp, sothat the timing remains constant even after long service. It is evidentthat the liner d may be made not only of steel but also of brass oroffother suitable material. VVThe pistons l5 `haverollers 43 `whichare-pressed against the camsl3i `by springs IM.I Thesprings bear'atone4end against spring washers 451 and `at the other endagainstthe`c`asingl. i V e While thepumps described aboveand illustrated invthe drawings are particularly `adapted foruse in providing a` limitedmaximum e fuel @feed to internal combustion engines, -it will be obviousvthat vin, the `broad sense such pumps are of `general applicationwherever `a limited maximum output of' pumped liquid is desired.` i

It will therefore be seenthat I have provided a construction whichsatisfies thebbjects enu-` merated above and one which constitutes avaluable advance in the art.` While'I have vshown the invention incertain physical embodiments, it isfto,` beI understood `thatmodifications of the structure shown maybe made by those vskilled inthisartwithout departing from my invention as expressed in `the claims whichfollow.

WhatI claimis: y l; Afuel pump comprising a pump casingprovided separatepump cylinder spaces, a

commonfinlet passage provided with ,channels leading to the individual"spaces, a `return pasage provided with channels leading from saidspacesia fuel controlling element in the said inlet passageresponsivetothe pressure of the fuel in said returnpassage, and a tnrottlingf`device arranged between. the return passage,` and theinlet passage. i

element in both directions. e i 3. A fuel pump comprising a pump casingpro` vided with separateQpump cylinder spaces, a common inlet passageprovided with channels leading tothe individual spaces, a return passageprovided with channels `leadingfrom said spaces, `a piston-shaped hollowsleeve in said inlet passage having a throttle opening in the wallnofsaid pistonto form aconnection between the inlet and `return, passages,`said piston being subjected to the pressure of the fuel within saidreturn passageeand said sleeve as a whole being` axially shiftable inthe inlet passagev under `the actionof such` pressure, the walls, ofsaid sleeve beingprovided With-throttle openings connecting the interiorof saidsleeve with the channels leading to the cylinder spaces, andspring mean for biasing said sleeve one direction.

' 4; Fuelfeed controlling apparatus for internal combustion enginescomprising, in combination, a device includinga pump cylinder space, an

inlet passage leading `to said cylinder space, a

delivery passage leading from said cylinder space, a returnpassageleading from said cylinder space to said' inlet passage,andthrottling means intermediate said return and inlet passages formain- A i "lo taining @the pressure of the` fuel in said return passagesubstantially proportionate to fthe amount of fuel flowing back to saidreturn passage`,"and means responsive to said pressure for varying thedelivery of fuel to the engine. 5L Fuelfeed `coritrollingapparatus forinternal combustionengines comprising, in combination, `a deviceincluding a pump `cylinder space, a

` source of fuel supply for saidcylinder space, a

delivery passage leading from said cylinder space, a return passageleading from said cylinder space to saidv source of fuel supply,` andthrottling 1 means intermediate saidr return passage and said source offuel supply formaintaining the pressure of the fuel insuch returnpassage substantially proportionate to'the yamount of` fuel flowing backthrough said return passage, and means responsive to" said pressure forvarying the delivery ofV fuel tothe engine. i

, 6. Fuel feed controlling apparatus forinternal combustion enginescomprising, in combination, a device including a pump cylinder space, an

inlet passage` leading thereto, a delivery passage leading therefrom, areturn passageleading from said cylinder space to said inlet passage,means for establishing a pressure differential between said inlet andreturn passages, means responsive to said pressure differential forcontrolling the delivery of fuel to the engine, and spring means lforbiasing said controlling means. i

7. A fuel pump, comprising,.in combination, a pump casing including acylinder space,` an inlet passage, a canal leading to the cylinderspace, a delivery passage leading from the cylinder space, a returnpassage connected to thecylinder space, and a regulatingdevice forcontrollably interconnecting said inlet passage with said canal, saidregulating device being subjected to and movable by the pressure of thefuel `in said return passage,

fand' being provided with a throttle opening interconnecting said returnpassage with said inlet 8. The combination according to claim 7, inwhich said regulating device includes a hollow sleeve having transversebores interconnecting `said inlet passage with said canal.

9. The combination according to claim '7, in which said regulatingdevice is in the form of an axially adjustable `slide valve.

10. The combination according to claim 7, in

which said regulating device includes a hollow sleeve closed at one endto form a piston face subljected to the pressure of the fuel in thereturn piston face.`

passage, said sleeve having `transverse bores interconnecting said inletpassage with said canal, said thirottle opening extending through saidl1. A pump comprising., incombination, a pump casing having separatepump cylinder spaces, a common `inlet passage,` canals leading from saidpassage to individual cylinderspaces, a

common return passage, other canals leading from said `cylinderspaces tosaid return passage,

and a controlling device in said inlet passage having `throttlingopenings adapted to adjustably control the communication 4between saidinlet passage land the` canals leading to the cylinder spaces, saiddevice including means responsive -"to the pressure in said returnpassage for varying the effective `cross-section of said communicatingv65 openings. i e

12. A liquid pump comprising in combination,

' a cylinder casing having at least two pump spaces and pistons in saidspaces, eachpiston having a beveled control edge, meansfor adjustingeach piston independently ofthe other, a com-mon inlet passage leadingto said cylinder spaces, a return passage leading from saidcylinderspaces to said inlet passage, throttling means `intermediate said returnand inlet passages for` maintaining the pressure of the fuel in saidreturn "passage sub- 14. The combination according to claim 12,

in which said independent adjusting means includes a toothed sector,longitudinally shiftable upon but non-rotatably connected to eachpiston, and a locking device engaging the toothed sector. p

15. The combination according to claim 12, in which said independentadjusting means includes a toothed sector, longitudinally shiftable uponbut non-rotatably connected to each piston, and

a set screw adjustable from without said pump casing, engaging with theteeth of the toothed sectors.

16. The combination according to claim 12, in

which said pump casing is formed from cast iron and said cylinder spacesare provided with smooth liners of another material.

17. The combination according to claim 12, in which said pump casing isformed from cast iron and said cylinder spaces are provided with steelliners.

18. The combination according to claim 4, in combination with a` pumppiston in said pump cylinder space, and means for maintaining the amountof fuel returning to said return passage substantially constant perworking stroke of said piston.

19. The combination according to claim 4, in combination with a pumppiston in said pump cylinder space, anda control groove Xed on saidpiston, communicating with said cylinder space and opening and closingsaid return passage at a constant point of time during the stroke of thepump piston to maintain the amount of fuel returning to said returnpassage substantially constant per working stroke of said piston.

v20. The combination according to claim 4, in combination With a pumppiston in said pump cylinder space, said piston being provided with acontrol edge oblique to the axis of said piston for controlling theconnection between said inlet passage and said cylinder space, and witha control groove extending substantially perpendicularly to the axis ofsaid piston for controlling the connection between said return passageand said cylinder space, and means for rotating said piston, whereby thetime relationship of the control of the connection between said inletpassage and said cylinder space may be varied while that of the controlof the connection between said return passage and said cylinder spaceremains substantially constant per working stroke of said piston.

21. The combination according to claim 4, in which said last meansdecreases the amount of fuel owing to the engine upon an increase ofpresure of the amount of return fuel.

22. In a iluid pump including at least one pump cylinder space having apiston therein, an inlet passage connected to said cylinder space, adelivery passage leading from said cylinder spa-ce, a return passageleading from said cylinder space, and regulating means in said inletpassage responsive to the pressure within said return passage forvarying the amount of fluid supplied to said cylinder space.

23. The combination according to claim 22, in which said regulatingmeans includes a slide valve mounted for reciprocal movement in saidinlet passage.

24. In a fluid pump including at least one pump cylinder space having apiston therein, an inlet passage connected to the cylinder space, adelivery passage leading from the cylinder space, a return passageleading from said cylinder space to said inlet passage, and regulatingmeans in said inlet passage responsive to the pressure differentialbetween said inlet and return passages for varying the amount of fluidsupplied to said cylinder space, said regulating means including meansintermediate said return and inlet passages having an interconnectingthrottling bore for establishing a pressure differential between saidinlet and return passages.

25. In a uid pump including at least one pump cylinder space having apiston therein, an inlet passage connected to the cylinder space, adelivery passage leading from the cylinder space, a return passageleading from said cylinder space to said inlet passage, and regulatingmeans in said inlet passage movable in one direction or the other inaccordance with the diierence in pressure within said inlet and returnpassages for varying of the amount of iiuid supplied to said cylinderspace, said regulating means including means intermediate said returnand inlet passages having an interconnecting throttling bore forestablishing a pressure differential between said inlet and returnpassages.

26. The combination according to claim 25, in combination with springmeans for opposing movement of said regulating means by the pressurewithin said return passage.

27. In a uid pump including at least one pump cylinder space having apiston therein, an inlet passage for said cylinder space, a canal insaid pump, opening into said inlet passage and said cylinder space forconducting fluid to the latter from said inlet passage, a return passageleading from said cylinder space to said inlet passage, and an axiallyshiftable slide valve movable in one direction or the other inaccordance with the difference in pressure Within said inlet and returnpassages for varying the ow of uid from said inlet passage to saidcanal. said slide Valve including means intermediate said return andinlet passages having an interconnecting throttling bore forestablishing a pressure differential between said inlet and returnpassages.

28. In a fluid pump including at least one pump cylinder space having apiston therein, an inlet passage for said cylinder space having a canalleading to said cylinder space, a delivery passage leading from saidcylinder space, a return passage leading from said cylinder space tosaid inlet passage, and an adjustable hollow slide valve open at oneend, axially sliiftable Within said inletl passage and having a radialopening therethrough interconnecting said canal with the hollow portionof said slide valve for controlling the flow of fluid from said inletpassage to said cylinder space, said slide valve being mov able in onedirection in accordance with the pressure within said return passage,said slide valve including means intermediate said return and inletpassages having an interconnecting throttling bore for establishing apressure differential between said inlet and return passages.

29. The combination according to claim 28, in

pump cylinder space having a piston therein, an y inlet passage leadingto said cylinder space and having a` controlling canal, a hollow slidevalve axially shiftable within said inlet passage for varying theeffective cross-sectional area of said canal, provided with an openingfrom its outer surface to the interior hollow portion for interconnecting the latter with said canal, and hav ing one end incommunication with said inlet passage and the other end with `a throttleopen ing therethrough leading from said inlet passage, a deliverypassage leading from said cylinder space, and a return passage *forguiding fluid under pressure from said cylinder space against the end ofthe hollow slide valve provided with the throttle opening.

31.'In a fluid pump including at least one pump cylinder space havingiapiston therein, an inlet passage having an opening into said cylinderspace, a hollow cylindrical slide valve having a controlling boretherethrough, mounted for re-v ciprocatory movement within said inletpassage for controlling the iiow of uid through said opening,` means formoving said slide valve, and a delivery passage leading from saidcylinder Vspace.

32. In a fuel pump having a cylinder space and a piston therein, aninlet passage leading to the pump cylinder space, having a controllingcanal, and a second passage leading from the pump cylinder space, thecombination of an axially adjustable piston-shaped regulating member insaid inlet passage for varying the effective crosssection of saidcontrolling canal, said member being directly subjected on one side tofuel pressure in the passage leading from the pump cylinder space, insuch a manner that upon an in crease in pressure above a predeterminedamount in said second passage, said member is moved to decrease theeffective the crossmsection of said inlet passage and lessen the amountof fuel how-m ing to the pump cylinder space.

33. The combination according to claim 32, in which said second passageleading from the pump cylinder space is a return passage which, n

carries back a part of the pumped fuel into the inlet passage so thatthe regulating member acts under pressure of the fuel in said returnpassage.

the `action of the return passage pressure upon said member. Y

SAMUEL MEISWINKEL;

